High-voltage transmission power lines strung from support towers form the backbone of the nation's electric power grid. Many of the power lines supported by nearly the multitude of towers run through isolated areas as they deliver electricity from generating plants to cities.
Continuous monitoring of electrical power lines, and in particular of high-voltage overhead lines, is essential in order to timely detect anomalous conditions, which could lead to an outage. In some cases, monitoring allows avoiding the outage, for example, by reducing the power transmitted by an overheated conductor while in other cases (e.g., cable in a wind storm) a localized outage is unavoidable, but timely intervention (e.g., by using monitoring information to redirect power flow) can avoid its propagation through the power grid leading to a generalized blackout.
Conventional approaches to monitor power lines can be time consuming, inaccurate, or require the actual presence of an engineer to physically conduct the measurement. For example, reflector-less laser technology is used for transmission and distribution applications such as sag profiling, measuring the heights of attachment points or a conductor from the ground, verifying vegetation clearances and determining the location for your guy wire. However, this technique is limited in that a person must stand at the location and measure the distance, height, and clearance values necessary to make critical decisions.
Other conventional methods use a time-domain reflectometer (TDR) to measure the change in impedance when a line is closer to the ground, but such a system does not provide very high accuracy as needed to predict power line failure.
Therefore, it would be advantageous to provide a compact, lightweight sensing device that measures at least one characteristic of an overhead power line that may be readily attached and removed from a power line.